The theoretical relationships are presented for determining the output amplitude and phase of each small signal when commonly amplified with a large signal by a memoryless nonlinear amplifier. Both the amplitude and phase of each output small signal depend on the input amplitude of the large signal and on the AM/AM and AM/PM characteristics of the nonlinear amplifier. If the nonlinear amplifier is a hard limiter without AM/PM conversion, then the well-known result can also be derived from a general formula developed in this paper. A numerical example is given and confirmed by laboratory measurement.

A problem associated with signal power control during multicarrier transmission in the presence of an amplifier nonlinearity in a satellite communications channel is analyzed. The problem is to calculate input carrier power levels wheii output carrier power levels are given. The Fletcher-Powell optimization technique is used for a small number of transmitted carriers, and an example shows the effect of weak signal suppression in the presence of large signal(s) because of nonlinear effects. This technique is applied to three types of transponder nonlinearities to illustrate realistic cases. The Gaussian assumption is used for a large number of carriers. Cases in which one or two input signals are much larger than the other signals are also treated.